Systems that process image data at rates acceptable for automated diagnostic prescreening, automated diagnostic screening and automated diagnostic screening quality control include the system disclosed in U.S. Pat. No. 5,315,700, entitled "Method And Apparatus For Rapidly Processing Data Sequences", by Richard S. Johnston et al. issued May 24, 1994 which is incorporated by reference hereto. These systems process images of biological specimen slides such as Pap smear slides. The biological specimen is taken from a patent that is part of a patient population. These systems automatically review the slide and provide an analysis score. The performance of these systems and similar image analysis systems depend on many factors including: the cellular materials composition of the slides to be screened; the speed of the system to scan and process images; the regular patient population composition; the operational mode of the system including system specificity and system sensitivity; and the variations between specimens. The slide processing speed of such systems determines their capacity and thus their operational cost. These systems also have associated signal to noise characteristics. The signal comprises the abnormal cellular material on the processed slides. The noise comprises the artifact or normal cellular material misclassified as abnormal material by these systems. Poor signal to noise characteristics adversely effect the classification effectiveness of these systems.
For example, the task of examining biological specimen slides for the prescreening of cervical cancer demonstrates the need for increasing processing speed and accuracy of automated specimen screeners. Each biological specimen slide exhibits large variability in abnormal cell prevalence. To routinely achieve the high sensitivity required on low-prevalence abnormal specimens, specimens that have a low number of abnormal material, these systems must process a significant number, if not all, of the images taken of the biological specimen slide. Consequently, the number of images these systems must process determines system throughput. In the prior art, the number of images to process is predetermined based on predefined criteria. As a result, the prior art treated each biological specimen slide identically, disregarding data collected from the slide during processing, using a simple sequential test methodology. In some instances this may degrade the signal to noise characteristics of the analysis by including noisy information. The invention recognizes for the first time that an automated analysis achieves optimum signal to noise characteristics during processing. The invention further determines when to stop processing to prevent counterproductive analysis.
Therefore, the invention dynamically processes the biological specimen slide based on data collected from the slide to achieve higher accuracy as well as increased system throughput.